Kim Dae Seok, Cha Yun Jeong, Kim Mun Ho, Lavrentovich Oleg D, Yoon Dong Ki
Graduate School of Nanoscience and Technology and KINC, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
Department of Polymer Engineering, Pukyong National University, Busan 608-739, Korea.
Nat Commun. 2016 Jan 4;7:10236. doi: 10.1038/ncomms10236.
Soft materials with layered structure such as membranes, block copolymers and smectics exhibit intriguing morphologies with nontrivial curvatures. Here, we report restructuring the Gaussian and mean curvatures of smectic A films with free surface in the process of sintering, that is, reshaping at elevated temperatures. The pattern of alternating patches of negative, zero and positive mean curvature of the air-smectic interface has a profound effect on the rate of sublimation. As a result of sublimation, condensation and restructuring, initially equilibrium smectic films with negative and zero Gaussian curvature are transformed into structures with pronounced positive Gaussian curvature of layers packing, which are rare in the samples obtained by cooling from the isotropic melt. The observed relationship between the curvatures, bulk elastic behaviour and interfacial geometries in sintering of smectic liquid crystals might pave the way for new approaches to control soft morphologies at micron and submicron scales.
具有层状结构的软材料，如膜、嵌段共聚物和近晶相，呈现出具有非平凡曲率的有趣形态。在此，我们报道了在烧结过程中，即高温重塑过程中，对具有自由表面的近晶A膜的高斯曲率和平均曲率进行重构。气-近晶界面处交替出现的负、零和正平均曲率斑块模式对升华速率有深远影响。由于升华、凝聚和重构，最初具有负高斯曲率和零高斯曲率的平衡近晶膜转变为具有明显正高斯曲率的层堆积结构，这种结构在从各向同性熔体冷却得到的样品中很少见。在近晶液晶烧结过程中观察到的曲率、体弹性行为和界面几何形状之间的关系，可能为控制微米和亚微米尺度软形态的新方法铺平道路。
